Space station task force perspective

Space station planning quidelines; architecture; functions; preliminary mission data base; scope for international and commercial participation; schedules; servicing capability; technology development; and space station program interfaces are discussed

Physical environment, nutrient budget, and ecology of Lake Moana-nui, Tokoroa

This report is based on fortnightly monitoring data collected over a 14 month period from November 2000 to January 2002 and a survey of the lake bathymetry and vegetation distribution. The project also included a detailed investigation into the associations between macroinvertebrates and the native and exotic plants in the lake, and experiments evaluating the effects of the large populations of the water flea Simocephalus vetulus that the lake maintains on algal concentrations and therefore water clarity. The aim of this report is to present and discuss the results of the monitoring, surveys, and experiments in order to make recommendations for the future management and health of Lake Moana-nui

One-dimensional transient finite difference model of an operational salinity gradient solar pond

This paper describes the modeling approach used to simulate the transient behavior of a salinity gradient solar pond. A system of finite difference equations are used to generate the time dependent temperature and salinity profiles within the pond. The stability of the pond, as determined by the capacity of the resulting salinity profile to suppress thermal convection within the primary gradient region of the pond, is continually monitored and when necessary adjustments are made to the thickness of the gradient zone. Results of the model are then compared to measurements taken during two representative seasonal periods at the University of Texas at El Paso's (UTEP's) research solar pond

Land use, associated eel production, and abundance of fish and crayfish in streams in Waikato, New Zealand

The density and biomass of fish and crayfish, and the production of eels, was compared among streams in native forest, exotic forest, and pasture. Populations were estimated by multiple-pass electroshocking at 11 sites in hill-country streams in the Waikato region, North Island. Three sites were in native forest, four in exotic forest, and four in pasture. Length of stream sampled at each site was 46-94 m (41-246 m2 in area), and catchment areas up stream of the sites ranged from 0.44 to 2.01 km2. A total of 487 fish were caught. The species were longfinned and shortfinned eels, banded kokopu, Cran's and redfinned bullies, and common smelt. Eels were the most abundant fish in all three land-use types, and shortfinned eels were more abundant at pastoral sites (mean density 1.11 fish m-2) than longfinned eels (mean density 0.129 fish m-2). Banded kokopu were present only at forested sites. Mean fish densities were greater at pastoral sites (1.55 fish m-2) than under either native forest (0.130 fish m-2) or exotic forest (0.229 fish m-2). Mean fish biomass was also greater at pastoral sites (89.7 g m-2) than under native forest (12.8 g m-2) or exotic forest (19.3 g m-2). Longfinned eels made a greater contribution to the fish biomass at all sites than did shortfinned eels. Densities of crayfish were high (0.46-5.40 crayfish m-2), but were not significantly different between land-use types. Crayfish biomass ranged from 1.79 to 11.2 g m-2. Total eel production was greater at pastoral sites (mean 17.9 g m-2 year-1) than at forest sites (mean 2.39 g m-2 year-1)

CHOICE SET CONSIDERATIONS IN MODELS OF RECREATION DEMAND: HISTORY AND CURRENT STATE OF THE ART

Demand and Price Analysis,